The invention relates to self-adhesive polymerizable monomers suitable for dental and medical applications.
Conventional dental/medical compositions such as cements are either water-based ionic cements or resin based materials. The water-based cements have the advantage of a modest adhesion to hard tooth tissues and of a high fluoride ion release from inorganic filler material. They have the disadvantage of high water solubility, low abrasion resistance and an excessive opacity. The resin-based materials have the advantage of excellent mechanical properties, a suitable opacity and low water solubility. They have the disadvantage of a lack of adhesion, a very poor release of fluoride ions from an inorganic filler and a high shrinkage.
It has already been known to improve the adhesion of resin-based dental/medical composites by incorporation of phosphoric acid ester groups or carboxylic ester groups (U.S. Pat. Nos. 399,754, 2,709,690, 4,514,342, 4,806,381, DE-OS 3536077, DE-OS 2711234, EP 0058483, DE-OS 3150285, E. Masuhara et.al. Rep. Inst. Med. Dent.Eng. 1 (1967) 29-33, M. Takeyama et. al. J.Soc.Dent.Appar. 19 (1978) 179-185). However, the adhesion is still insufficient. Moreover compositions with such monomers have a high shrinkage during polymerization.
It is a problem of the invention to provide a self-adhesive polymerizabe monomer for dental compositions and a process for preparing said self-adhesive polymerizabe monomer, whereby the dental/medical composition which combine the favourable characteristics of water-based and resin-based conventional materials and have a high adhesion to hard dental tissue and lower shrinkage.
A self-adhesive polymerizable monomer that comprises at least two polymerizable moieties (i), at least one substituted or unsubstituted C3 to C20 alkylene or at least one substituted or unsubstituted C5 to C20 cycloalkylene (ii) that is connected with (i) by a linking unit, at least an acidic moiety selected from the group (iii) 
or at least an ionic moiety selected from the group 
which is connected with (ii) and wherein
the R1, R2, R3 are the same or different substituted or unsubstituted residues of hydrogen or an alkylene having 2 to 20 carbon atoms, a cycloalkylene having 5 to 20 carbon atoms, an aryl or a heteroaryl having 4 to 12 carbon atoms,
X is a cationic counterion such as 
xe2x80x83and
Y is an anionic ion such as OHxe2x88x92, Fxe2x88x92, Clxe2x88x92, Brxe2x88x92, Tosylxe2x88x92.
The polymerizable groups preferably are methacrylic or acrylic groups. The linking unit preferably is an ether or a thioether, an ester, a carbonate, a urethane moiety.
Preferably, the self-adhesive polymerizable monomer is characterized by the following formulas: 
wherein
R4 denotes a substituted or unsubstituted alkylene having 3 to 20 carbon atoms,
Z is an acidic moiety selected from the group 
xe2x80x83or an ionic moiety selected from the group 
xe2x80x83wherein
the R1, R2, R3 are the same or different substituted or unsubstituted residues of Hydrogen or an alkylene having 2 to 20 carbon atoms, a cycloalkylene having 5 to 20 carbon atoms, an aryl or a heteroaryl having 4 to 12 carbon atoms,
X is a cation such as ammonium, sulfonium, sodium, potassium, strontium, calcium or magnesium salts 
xe2x80x83and
Y is an anion such as OHxe2x80x94, Fxe2x80x94, Clxe2x80x94, Brxe2x80x94, Tosylxe2x80x94.
Most preferably the self-adhesive polymerizable monomer is characterized in the following formula: 
The self-adhesive polymerizable monomer is used in a dental/medical composition comprising a filler, a polymerizable monomer, a polymerization initiator and a stabilizer.
The polymerizable monomer preferably is a mono- and polyfunctional (meth)acrylate, such as a reaction product of a polyepoxide with (meth)acrylic acid), a polyalkylenoxide di- and poly(meth)acrylate, an urethane di- and poly(meth) acrylate, preferably were used Bis-GMA diethylenglycol dimethacrylate, triethylenglycol dimethacrylate, 3,(4),8,(9)-dimethacryloyloxymethyltricyclodecane, dioxolan bismethacrylate, glycerol trimethacrylate, furfuryl methacrylate in a content of 5 to 80 wt-%.
The polymerization initiator is a thermal initiator, a redox-initiator or a photo initiator.
As filler is an inorganic filler and/or an organic filler.
The self-adhesive polymerizable monomer is usable in a self-adhesive dental/medical composition characterized by the combination of
A an adhesion to dentine of at least 5 MPa
B a fluoride release of at least 1 xcexcg Fxe2x88x92 per week and per cm2 of the exposed surface of the composition
C an opacity of at least C0,7=40% and
D a compressive strength of at least 200 MPa.
The self-adhesive polymerizable monomer is usable in a self-adhesive dental/medical cement comprising
25 to 50 wt-% of a self-adhesive polymerizable monomer,
0 to 25 wt-% of a polymerizable monomer,
50 to 75 wt-% of a filler and polymerization initiator and stabilizers.
The self-adhesive polymerizable monomer is usable in a self-adhesive dental/medical composite comprising
15 to 50 wt-% of a self-adhesive polymerizable monomer of claims 1 to 3,
0 to 35 wt-% of a polymerizable monomer,
50 to 85 wt-% of a filler and polymerization initiator and stabilizers.
The self-adhesive polymerizable monomer is usable in a self-adhesive dental/medical sealant comprising
45 to 90 wt-% of a self-adhesive polymerizable monomer of claims 1 to 3,
0 to 45 wt-% of a polymerizable monomer,
10 to 55 wt-% of a filler and polymerization initiator and stabilizers.
The self-adhesive polymerizable monomer is usable in a self-adhesive dental/medical primer comprising
15 to 80 wt-% of a self-adhesive polymerizable monomer of claims 1 to 3,
0 to 65 wt-% of a polymerizable monomer,
0 to 65 wt-% of a filler and polymerization initiator and stabilizers
20 to 85 wt-% of a diluent and polymerization initiator and stabilizers.
An adhesive dental composite containing radiopaque fillers provides a radio-opacity of at least 2 mm/mm Al, preferably at least 3 to 7 mm/mm Al, most preferably at least 7 mm/mmAl.
The self-adhesive dental/medical composites have a fluoride release of at least 1 xcexcg/cm2, preferably at least 1-3 xcexcg/cm2, most preferably at least 3-10 xcexcg/cm2.
Furthermore the self-adhesive dental/medical composites show a opacity of at least 40%, preferably at least 20-40%, most preferably at least 5-20%.